Drilling tool for drilling into a sand and gravel layer

Abstract

The utility model relates to the technical field of drilling and exploration, disclose a kind of drill tool for sand and gravel layer drilling, including drill pipe, drill bit, auger drill pipe and casing assembly, wherein: the casing assembly is composed of pipe body, connecting rib and female joint, the female joint is coaxially arranged with pipe body, and is connected into an integral structure by multiple connecting ribs with pipe body;The auger drill pipe is located in pipe body, and the male joint on its top is screwed with the bottom of the female joint;The drill pipe is screwed with the top of the female joint;The drill bit is screwed in the bottom of the auger drill pipe.The utility model can reduce hole deviation, enhance the effect of wall protection, and also avoid coarse particles to affect drilling efficiency.

Description

Technical Field

[0001] This utility model relates to the field of drilling and exploration technology, and in particular to a drilling tool for drilling gravel layers. Background Technology

[0002] In drilling operations for anchor bolts, anchor cables, and steel pipe piles, gravel layers are frequently encountered. Currently, the common method is to directly connect the drill rod to a three-wing drill bit and use positive circulation mud for wall protection. This method is characterized by lightweight equipment, simple process, rapid entry and exit, and low cost. However, it has the following problems:

[0003] 1. Large borehole deviation: Taking φ130 borehole as an example, the three-wing drill bit is conical, and the upper drill rod is generally φ42. The annular gap between the drill rod and the borehole wall is large, and the rigidity of the drill bit inside the hole is poor. When drilling and applying pressure, the pressure transmitted from the drill rod to the drill bit is deviated, which causes the drill bit to be unable to drill vertically downward, and the borehole deviation rate cannot be guaranteed.

[0004] 2. Unstable borehole wall: When the three-wing drill bit is rotating, it has a significant impact on the strata in the surrounding area, and the newly formed borehole wall is most prone to collapse; at the same time, no mud cake has formed on the borehole wall, and the mud slurry wall protection effect is poor.

[0005] 3. Coarse particles accumulate at the bottom of the hole and are repeatedly crushed, resulting in low drilling efficiency: Due to the large annular gap between the drill rod and the hole wall, the flow rate of the circulating mud is slow. Coarse particles in the gravel layer cannot return to the hole with the mud and will fall and accumulate at the bottom of the hole, where they are repeatedly scraped and crushed by the drill bit, affecting drilling efficiency.

[0006] Based on this, this application provides a drilling tool for drilling gravel layers that can reduce borehole deviation, stabilize the borehole wall, and prevent coarse particles from settling to the bottom, in order to solve the above problems. Utility Model Content

[0007] The present invention aims to solve the technical problems existing in the prior art. To this end, the present invention provides a drilling tool for drilling through gravel layers that can reduce borehole deviation, stabilize the borehole wall, and prevent coarse particles from settling to the bottom.

[0008] The technical solution adopted by this utility model to solve its technical problem is:

[0009] A drilling tool for drilling gravel layers is provided, comprising a drill rod, a drill bit, a spiral drill rod, and a casing assembly, wherein: the casing assembly consists of a casing body, connecting ribs, and a female connector; the female connector is coaxially arranged with the casing body and is connected to the casing body as an integral structure by multiple connecting ribs; the spiral drill rod is disposed within the casing body, and its top male connector is screwed to the bottom of the female connector; the drill rod is screwed to the top of the female connector; and the drill bit is screwed to the bottom of the spiral drill rod.

[0010] In some alternative embodiments, the pipe body is further provided with at least one drain groove arranged in a ring along its length, the drain groove having a width of 5 to 10 mm.

[0011] In some alternative embodiments, the outer diameter of the tube is 0 to 10 mm smaller than the outer diameter of the drill bit.

[0012] In some alternative embodiments, the outer diameter of the auger drill rod is 2 to 4 mm smaller than the inner diameter of the tube.

[0013] In some alternative embodiments, the pitch of the helical blades on the auger rod is 1.2 to 1.5 times the diameter of the coarse particles produced by the drill bit.

[0014] In some optional embodiments, the upper surface of the spiral blades of the auger drill rod is further provided with a plurality of anti-slip strips at equal intervals, the height of the anti-slip strips being 8 to 12 mm.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] 1. This utility model can achieve guiding and straightening by matching the casing body of the casing assembly with the borehole, so as to reduce borehole deviation;

[0017] 2. The casing assembly generates radial support force on the borehole wall, ensuring timely wall protection for newly formed sections. Furthermore, the outer wall of the casing repeatedly contacts and grinds against the borehole wall to form mud, further enhancing the wall protection effect.

[0018] 3. When drilling, the auger rod generates an upward thrust on the mud, which, together with the fluid flow, discharges the fine particles generated by the drill bit with the positive circulation mud out of the borehole, while the coarse particles remain in the annular space between the casing assembly and the auger rod, thus preventing the coarse particles from settling to the bottom.

[0019] 4. The drain groove provided on the tube body of the casing assembly can discharge some of the fine particles in the mud from the drain groove and squeeze them into the borehole wall to form mud skin, thereby improving the wall protection effect. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0021] Figure 1 This is a schematic diagram of the structure of the drilling tool for drilling gravel layers provided by this utility model;

[0022] Figure 2This is a schematic diagram of the sleeve assembly provided by this utility model;

[0023] Figure 3 This is a schematic diagram of the structure of the spiral drill rod provided by this utility model.

[0024] The attached diagram lists the components represented by each number as follows:

[0025] 1—Drill pipe, 2—Drill bit, 3—Auger pipe, 3.1—Auger blade, 3.2—Anti-slip strip, 4—Casing assembly, 4.1—Casing body, 4.1.1—Drainage groove, 4.2—Connecting rib, 4.3—Female connector. Detailed Implementation

[0026] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0028] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] Furthermore, the terms "installation," "connection," and "linking" used in this utility model should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0031] Example 1

[0032] As attached Figure 1 To be continued Figure 3 As shown, this embodiment provides a drilling tool for drilling gravel layers, including a drill pipe 1, a drill bit 2, a spiral drill pipe 3, and a casing assembly 4, wherein:

[0033] The casing assembly 4 consists of a casing body 4.1, connecting ribs 4.2, and a female connector 4.3. The female connector 4.3 is coaxially arranged with the casing body 4.1 and is connected to the casing body 4.1 as an integral structure by multiple connecting ribs 4.2. In this embodiment, four connecting ribs 4.2 are provided, which are evenly distributed in a ring on the casing body and welded to the casing body and the female connector. Preferably, in this embodiment, the length of the casing body 4.1 is about 1m, and its outer diameter is 0-10mm smaller than the outer diameter of the drill bit 2. This can play a guiding and straightening role, reducing drilling deviation. At the same time, the casing body generates radial support force on the borehole wall, ensuring timely wall protection of the newly formed hole section. Furthermore, the repeated contact and grinding between the outer wall of the casing and the borehole wall forms mud skin, further enhancing the wall protection effect.

[0034] The auger drill rod 3 is disposed inside the tube body 4.1, and its top male connector is screwed to the bottom of the female connector 4.3. Preferably, in this embodiment, the outer diameter of the auger drill rod 3 is 2-4 mm smaller than the inner diameter of the tube body 4.1, and the pitch of the auger blades 3.1 on the auger drill rod 3 is 1.2-1.5 times the particle size of the coarse particles produced by the drill bit 2. In this embodiment, the auger drill rod generates an upward thrust on the drilling mud during drilling, which, together with the fluid flow, discharges the fine particles produced by the drill bit with the positive circulation drilling mud out of the borehole, while the coarse particles remain in the annular space between the tube body and the auger drill rod of the casing assembly, preventing the coarse particles from settling to the bottom.

[0035] The drill rod 1 is screwed to the top of the female connector 4.3, and the drill bit 2 is screwed to the bottom of the spiral drill rod 3.

[0036] Specifically, during drilling operations, drill cuttings enter the casing assembly under the combined action of the fluid flow and the auger rod. Small particles in the drilling mud flow out from between the casing and the female connector under the combined action of the auger thrust and the fluid flow, and return to the borehole through the annular gap between the drill rod and the borehole wall. Large particles in the drilling mud are deposited in the annular space between the auger rod and the casing. After drilling stops, the drill string is lifted and removed, and the coarse particles are discharged by inverting the drill string. If it is difficult to discharge, the drill string can be disassembled and the auger rod can be removed from the casing assembly.

[0037] Example 2

[0038] Based on Example 1, as shown in the appendix Figure 2 As shown, in this embodiment, at least one drain groove 4.1.1 is arranged in a ring along the length direction on the pipe body 4.1. Preferably, there are 2 to 4 drain grooves in this embodiment, and the width of the drain groove 4.1.1 is 5 to 10 mm.

[0039] In this embodiment, the drainage groove set on the pipe body can discharge some of the fine particles in the drilling mud from the drainage groove during the drilling process, and squeeze them into the borehole wall to form mud cake, thereby improving the wall protection effect.

[0040] Example 3

[0041] Based on Embodiment 1 or Embodiment 2, this embodiment further provides a plurality of anti-slip strips 3.2 at equal intervals on the upper surface of the spiral blades 3.1 of the spiral drill rod 3. The height of the anti-slip strips 3.2 is 8-12mm, preferably 10mm.

[0042] When drilling stops, large particles stuck on the spiral blades are prone to sliding down. In this embodiment, an anti-slip strip (strip baffle) about 10mm high is provided on the spiral blades, which can effectively prevent large particles from sliding down.

[0043] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made using the content of this utility model specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A drilling tool for drilling through gravel layers, comprising a drill rod and a drill bit; characterized in that: It also includes auger drill pipe and casing assemblies, wherein: The sleeve assembly consists of a tube body, connecting ribs, and a female connector. The female connector is coaxially arranged with the tube body and is connected to the tube body as an integral structure through multiple connecting ribs. The auger drill rod is installed inside the pipe, and the male connector at its top is screwed to the bottom of the female connector. The drill pipe is screwed to the top of the female connector; The drill bit is screwed to the bottom of the auger drill rod.

2. The drilling tool for drilling gravel layers according to claim 1, characterized in that: The pipe body also has at least one drain groove arranged in a ring along its length, and the width of the drain groove is 5 to 10 mm.

3. The drilling tool for drilling gravel layers according to claim 1, characterized in that: The outer diameter of the tube is 0-10 mm smaller than the outer diameter of the drill bit.

4. The drilling tool for drilling gravel layers according to claim 1, characterized in that: The outer diameter of the auger drill rod is 2-4 mm smaller than the inner diameter of the tube.

5. The drilling tool for drilling gravel layers according to claim 1 or 4, characterized in that: The pitch of the helical blades on the auger drill rod is 1.2 to 1.5 times the diameter of the coarse particles produced by the drill bit.

6. The drilling tool for drilling gravel layers according to claim 1, characterized in that: The upper surface of the spiral blades of the spiral drill rod is also provided with several anti-slip strips at equal intervals, and the height of the anti-slip strips is 8-12mm.

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